Efforts are undertaken to determine whether phosphoprotein 48 (pp48) in any of its phosphorylated forms binds to components of cytochrome B558 using blotting or in the chromatography approaches. Also, the capacity of exogenous phosphorylated pp48 to activate respiratory burst oxidase in cell free systems from resting neutrophils will be assessed to determine if its phosphorylation is a critical event in activation of the oxidase.